Improvement in the manufacture of door-knobs



1. OTTN ER.

Manufacture of Door-Knobs.

INVENTOR WITNESSES Patented May 13, 1873.

UNITED STATES PATENT -OFFIGE.

JOSEPH OTTNER, OF BRIDGEPORT, CONNECTICUT.

IMPROVEMENT IN THE MANUFACTURE OF DOOR-KNOBS.

Specification forming part of Letters Patent No. 138,758, dated May 13, 1873; application filed April 7, 1873.

consists in casting the shell for knob in two parts, in an ordinary sandmbld, and in uniting-them with a ring of metal cast around their circumference, the object being to dispense with a core, and to facilitate their manu- I facture.

In the drawing, Figure 1 is a face view of the spindle portion of knob. Fig. 2 is a latitudinal section of knob. I

The shell I cast of metal, either with or without an outer casing, ornamented as shown in'p'atent of Christian Rebstock and Joseph Ottner, of February 14, 1873, in an ordinary sand-mold. I then turn a rabbet, as shown at b, to keep the two portions of knob in proper position for uniting. I also turn in the grooves 2 2, by which the parts are held together by the ring C. I then set the shell in a sand or metal mold in which the contour of the ringC has been prepared in addition to that of the knob, and then pour molten metal around them, which unites the parts firmly together. I then finish the ring in a lathe,

leaving the periphery smooth and true, and

avoid the imperfections of uniting the parts when faced with a thin metal shell whose edges have to be turned over each other, and are easily bent or torn around the periphery.

What I claim as new, and desire to secure by Letters Patent, is- I 1. The method of casting and preparing the shells for metallic knobs, as described and set forth.

2. The uniting of the shells of a metallic door-knob by a metal ring cast to the parts and finished, as described and set forth.

In testimony whereof I have signed my name to this specification before two subscribing witnesses.

JOSEPH OTTNER.

Witnesses:

A. SKAATS, Gno. Z. SKAATs. 

